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INVESTMENT IN UNCONSOLIDATED JOINT VENTURES (Mortgage Maturities) (Details) - USD ($)	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020	May 31, 2018	Oct. 13, 2016
Annual maturities of mortgage debt
2021-current maturities	$ 2,549,000
2022	79,941,000
2023	25,419,000
2024	11,269,000
2025	21,709,000
Thereafter	142,777,000
Total	283,664,000
Less: unamortized deferred financing costs	(1,225,000)
Secured Debt	$ 282,438,864	$ 283,444,533
Weighted average interest rate (as a percent)	3.91%
Effective interest rate (as a percent)	3.97%
Investment Properties
Annual maturities of mortgage debt
2021-current maturities	$ 217,796
2022	226,376
2023	235,293
2024	17,144,563
2025	10,254,197
Thereafter	138,865,231
Total	166,943,456
Less: unamortized deferred financing costs	(686,558)
Secured Debt	166,256,898		$ 166,357,134
Hamilton Essex 81
Annual maturities of mortgage debt
2025	10,000,000
Total	10,000,000
Less: unamortized deferred financing costs	(58,604)
Secured Debt	9,941,396		9,927,607
345 Franklin
Annual maturities of mortgage debt
2021-current maturities	217,796
2022	226,376
2023	235,293
2024	244,563
2025	254,197
Thereafter	7,865,231
Total	9,043,456
Less: unamortized deferred financing costs	(46,609)
Secured Debt	8,996,847		9,199,730
Hamilton Minuteman
Annual maturities of mortgage debt
Thereafter	6,000,000
Total	6,000,000
Less: unamortized deferred financing costs	(83,540)				$ (123,000)
Secured Debt	5,916,460		5,908,276
Hamilton on Main Apts
Annual maturities of mortgage debt
2024	16,900,000
Total	16,900,000
Less: unamortized deferred financing costs	(50,829)
Secured Debt	16,849,171		16,833,120
Dexter Park
Annual maturities of mortgage debt
Thereafter	125,000,000
Total	125,000,000
Less: unamortized deferred financing costs	(446,976)
Secured Debt	$ 124,553,024		$ 124,488,401	$ 82,000,000